The present invention relates to a hitch assembly for an agricultural tractor.
Current production agricultural tractors have implement hitches which have pivotal draft links for coupling to an implement or to a quick coupler. Such draft links are subject to side loads and will swing laterally when the tractor turns while an attached implement is still in the ground. U.S. Pat. No. 4,216,975, issued Aug. 12 1980 describes a tractor hitch assembly with left and right sway links which can be positioned to lock or to permit lateral sway of the draft links. It is also known to use frame-mounted sway blocks to limit lateral motion of the hitch draft links. It is also known to taper conventional sway blocks in the vertical direction to permit maximum sway when the hitch is lowered and to permit no sway when the hitch is in a raised transport position. However, as the tires used on agricultural tractors become larger, the draft links have to be lower relative to the frame of the tractor to maintain the required height off of the ground. If, to limit lateral motion of the hitch, the sway blocks are extended down below the tractor frame, hitch side loads can then damage the unsupported lower portion of such sway blocks. It would be desirable to have a hitch assembly for such tractors with large tires wherein the sway blocks are protected from damage by side forces on the hitch links.
Accordingly, an object of this invention is to provide a hitch assembly for tractors with large tires.
A further object of the invention is to provide such a hitch assembly sway blocks which will limit and not be damaged by lateral motion of the hitch.
These and other objects are achieved by the present invention, wherein a hitch assembly is mounted on a frame of an agricultural tractor. The hitch assembly includes a pair of draft links pivotally mounted on the frame, a drawbar support fixed to the frame between the draft links, and a pair of sway blocks fixed to opposite sides of the frame. Each sway block has an upper end fixed to a side of the frame and extends generally downwardly to a lower free end. The lower free end of each sway block is positioned below a plane defined by a bottom surface of the drawbar support. Each sway block is preferably tapered from a wider front side to a narrower rear side to form an inner surface which faces inwardly and rearwardly. A wedge plate is mounted beneath the drawbar support. The plate extends generally laterally from a left end surface to a right end surface, and each end surface is slanted in order to matingly engage the inner surface of a corresponding one of the sway blocks. The wedge plate is longer than the drawbar support, and projects laterally out from the left and right ends of the drawbar support. As a result, the wedge plate end surfaces engage the inner surfaces of the corresponding inner sway blocks and supports them against side forces applied by the draft links.